Explain how Bohr's atomic model explains the emission and absorption of radiation.

Bohr's atomic model states that electrons move in definite orbits possessing definite amount of energy. In other words the electrons in the first orbit or shell possess a definite energy, En₁ while the electrons which move in second shell or orbit possess another definite energy, En₂.
According to Bohr, an electron which moves from energy level En₁, to energy level, En₂, should absorb energy equal to En₂ – En₁ and it results in the absorption of energy and since absorption spectra.
When an electron jumps from higher energy level, En₂ to lower energy level, En₁ , it gives out or radiates energy equal to En₂ – En₁ , and gives emission spectra elements. Thus Bohr's theory explains this spectra of the elements.